Propeller



July 14, 1931. F. A. GILL 1,814,595

PROPELLER Filed May 14, 1930 3 Sheets-Sheet 1 driven fax 4%?75655 4 g F a y 7 ifa a F. A. GILL PROPELLER Filed May 14, 1950 3 Sheets-Sheet I 2 July 14, 1931. F. A. GILL 1,814,595

PROPELLER Filed May 14, 1930 3 Sheets-Sheet 5 Qiwuen 767 Frciinana 09? 617/ Federated July it, 19311 inflates caries FERDINAND A. GILL, F GHICAGO, ILLI'NUIS FROPELLER Application filed May 14,

means therefor which enable the blades to be quickly, surely, evenly and synchronously inclined from zero to any practical working m angle.

lit is frequently desirable to change the angle of inclination of the blades of propellers, and particularly so with air craft propellers, to compensate for different engine speeds. llhe an le at which propellerblades operate most e ciently also depends upon the density of the medium in which the propeller revolves. For example, an airplane will operate more eficiently at high altitudes with the propeller blades inclined substantially to the plane of rotation, while in low altitudes where the atmosphere is more dense, it is desirable to have the blades at a smaller angle of inclination to the plane of rotation. In the control of dirigibles and in checking the speed of airplanes when landing on a comparatively restricted surface, as for example, the deck of a ship, it becomes important to completely reverse the propeller blades, so as to change the direction of thrust. The invention contemplates means for shifting the angle of inclination of the propeller blades during flight. This result is accomplished by means of control levers, positioned within easy access of the pilot, operable to cause the rotation of the propeller to shift the blades and another object of the invention is the provision of improved means operable while the propeller is rotatingfor shifting the angle of the propeller blades with respect to their plane of rotation and of means for locking the blades in adjusted position.

A further object is to provide improved means by which the blades automatically lock and hold their adjustment after being set at any angle.

Still other objects of the invention include the provision of a propeller construction, whereby the shifting of the inclination o the blades can be efi'ected with a minimum of 1930. Serial No. 452,324.

mechanism at any desired speed, and whereby the shifting mechanism is contained entirely within or mounted on the hub of the propeller and requires no modification of the propeller mechanism other than of the proat peller hub.

' A still further object is'to provide propeller apparatus of the kind described, which is simple in construction, inexpensive to manufacture, efficient in operation and rugged. do

Yarious other objects and advantages of the construction herein shown and described will be obvious to those skilled in the art from the disclosure herein given.

To this end, my invention consists in the as novel construction, arrangement and combination of parts herein described and shown, and more particularly pointed out in the claims.

Referring now to the drawings, forming a part of my specification and illustrating certain preferred embodiments of my inven tion.

Fig. 1 is a partial section and elevational view of a propeller hub in which one device embodying my invention is mounted;

Fig. 2 1s a sectional View along the line 2-2 of Fig. 1;

Fig. 3 is a sectional view along the line 33 of Fig. 1, drawn to a larger scale;

Fig. 4 is a sectional view along the line 4+4 of Fig. 3; e

Fig. 5 is a sectional View along the line 55 of Fig. 1, drawn to a larger scale;

Fig. 6 is a sectional view along the line 6-6 of Fig. 3; e

Fig. 7 is a sectional view along the line 7-7 of Fig. 2, drawn to a larger scale;

Fig. 8 is a partial sectional elevational view along the line8-8 of Fig. 7;

Fig. 9 is a sectional view along the line 99 ofFig. 3; and

Figs. 10 and 11 are enlarg'cd sectional views showing details of the device. 7

Referring now more particularly to the t5 drawings, forming part of this specification,

a rotatable shaft 16, driven by .an engine (not shown) actuates a pair of propeller f blades 15R and 15L. The propeller blades are operatively'connected with the shaft 16 by a hub or disk 19 fixedly mounted on the forward end of the shaft. The front end of the shaft 16 is slightly tapered and terminates in a threaded cylindrical end member 23 of relatively small diameter. The-member 23 projects through the hub disk 19 and has a nut 22 threaded thereon to fasten the disk to the shaft. The disk 19 is of substantial thickness and the nut 22 is positioned in a recess 1 1 provided for that purpose in the disk. The threaded member 23 and the nut 22 are thereby substantially contained within the disk 19 and project only slightly, or not at all, beyond the face of the disk. The disk 19 has a rearwardly extending integrally formed sleeve 20 closely fitting the tapered end of the shaft 16 and providing a rigid connection of the shaft with the disk. A flange 2 1, formed on the margin of the disk 19 provides a mounting means for a shield 17. The shield 17 is connected with the flange 2 1 in any suitable wa such as welding, riveting, or the like. The shield 17 tapers outwardly to a blunt point at its front end 'to provide a conoidal housing for the disk 19 and the means operatively connecting the inner ends of the blades 15R, and 15L with the disk.

The disk 19, the shield 17, and all of the other members mounted upon the disk in cluding the blades 15R and 15L, are rotated by and with the shaft 16. A disk member 25 is positioned a short distance back of the disk 19 to provide a bearing for the shaft 16. The disk 25 may be a part of the engine structure, 9r it may be a separate member supported in any suitable manner, either upon the englue or the frame structure of the plane. The stationary disk 25 is slightly larger in diameter than the rotating disk 19 and the space between the disks is enclosed by a casing 18. i

The shield 17 is suitably apertured to receive the inner ends of the blades 15R and 15L and is provided with thickened portions 21 adjacent the blades. The thickened portions 21 provide the requisite rigidity for causing rotation of the blades 151?. and 15L as a unit with the casin 17. The inner end portions of the blades 15 and 15L positioned inside the casing 17 are trustro-conical in shape. The extreme inner ends of the blades 15R and 15L terminate in cylindrical members 30 of relatively small diameter. A bracket 29 on the front face of the disk 19 has its upper end in the form of a hollow cylinder to provide bearings for the cylindrical membersBO. A pair of frustro-conical sleeves 34;, each comprising two sections form bearing supports for the inner tapered ends of the blades. The outer ends of the sleeve 34 abut the shield 17 and their inner ends abut collars 33 fixedly mounted upon the members 30. The mounting of the blades 15R and 15L on the shield 17 and the bracket 29, cause the blades to rotate with the shield and the disk 19 as aunit. The sleeves 84 hold the blades 15R and 15L against outward radial movement while revolving.

Cam actuated mechanism, mounted on the disk 19 is operable, as desired, to rotate the blades 15R and 15L about their longitudinal axes. The blades 15R and 15L are normally locked against rotation relative to their longitudinal axes by teeth 51 which project through apertures provided in the sleeve sections 34, as best shown in Fig. 9. The inner tapered portions of the blades 15R and 15L are each provided with two rows of regularly spaced apart apertures 50, to receive the teeth 51 and to lock the blades against rotation. The teeth 51 are mounted on a plurality of hingedly connected sleeve sections 11 arranged in two pairs, each pair of sections 41, normally clamping about the sleeve sections 3 1. W hen the sleeve sections 41 are in their closed position, as indicated in Fig. 9, the oppositely positioned teeth 51 are contained within corresponding apertures 50 of the blades 15R and 15L and prevent rotation of the blades about their longitudinal axes. The sleeve sections 41 are pivotally mounted on pins 12 carried by supporting members 13 project ing from the disk 19. A tension spring 46 suitably mounted in a socket 15 tends to hold the sleeve sections in the relative positions shown in Fig. 9. The sections 11 adjacent the disk 19 are fixedly fastened to the disk by means of supporting members 17. The initial step in the rotation of the blades 15R and 15L about their longitudinal axes, for the purpose of changing their angle of inclination, is the removal of the teeth 51 from the apertures 50 in which they are positioned, which removal is accomplished by rotating a cam 5a. The cam 54 is shown in Fig. 9 as positioned between plates 14-, forming the free ends of the sleeve sections 4.1. The cam 54 is operatively connected with a slotted block 56 by means of a looped or U- shaped rod 55. The ends of the rod 55 are each fixedly connected to an end of the cam 54, and the middle portion of the rod is slidable in the block 56. By moving the block 56 from its full line position of Fig. 9, wherein the teeth 51 are in locking engagement with the blades 15R and 15L to the dotted line position, the cam 54 is caused to rotate and open up the sleeve sections 41 sufiiciently to remove the teeth 51- from the apertures 50. A longitudinally movable rod 57 projects through the disk 19 and provides a mounting and actuating member for the block 56. Longitudinal movement of the rod 57 accomplishes the engagement and disengagement of the teeth 51 with the blades 15R and 15L, by moving the block 56. The movement of the rod 57 is produced by cam actuated mechanism in a manner hereinafter more particularly described. In order that the blades 15R and 15L may be easily rotated about their longitudinal axes, upon removal of the teeth- 51 from the apertures 50, each of the blades is equipped with a race 37 containing balls 38 held within the race by the sleeve sections 34:. A pair of clamping members 35 fastened together by screw bolts 36 surround the sleeve sections 34.- and prevent spreading at the points where the races 37 are located.

The blades 15R and 15L each have a worm wheel 28 mounted on their inner ends adjacent the collars 33. Worms 27, engaging the worm wheels 28, are operable to rotate the blades 15R and 15L when unlocked by removal of the teeth 51. The worms 27 are mounted on brackets 31 and 32 projecting from the front end of the disk 19. A gear 63 is fixedly mounted on the upper end of each of the worms 27 in meshing engagement with a gear 64. The gear 641- is fixedly mounted on the lower end of a shaft 62, so that rotation of the shaft causes the two gears 63 and the worms 27 connected therewith,to correspondingly rotate in opposite directions. The shaft 62 is supported by bearing members 65 fastened to the disk 19 by screw bolts 66 and is rotatable by either a gear 67 or a gear 68, both fixedly mounted on the shaft. T he gear 67 meshes with a gear 72, mounted on an auxiliary shaft 69. The shaft 69 is supported by means of bearing blocks 70 fastened to the disk 19 by screw bolts 71. Rotation of the gear 68 in clockwise direction, as observed in Fig. 6, will actuate the shaft 62on which the gear is mounted. Rotation of the shaft 62 causes corresponding rotation of the gear 64, the gears 63, the worms 27, and the worm wheels 28, with the result that the blades 15R and 15L so rotate as to cause the top of the blades 15R and 15L to move away from the observer in Fig. 3.

Rotation of the gear 72 in clockwise direction,

as observed in Fig. 6 will oppositely rotate gear 67 with which it meshes, and cause the shaft 62 to rotate ina direction opposite to that caused by the clockwise rotation of the'gear 68. The resulting rotation of the blades 15R and 15L is opposite to that caused by the clockwise rotation of the gear 68.

Separate cam actuated mechanism, shown in detail in Figs. 10 and 11 are mounted on the shafts 69 and 62, respectively, to cause rotation of the gears 72 and 68 when it is desired to shift the angle of inclination of the blades 15R and 15L. Both of the cam actuated mechanisms rotate with the disk 19 and are normally perpendicular to the disk as shown in Fig. 10. A. third cam actuated mechanism shown in Fig. 6 is utilized to rotate the cam 54 to release the teeth 51 from holding engagement with the blades 15R- and 15L. The release of the blades 15R and 15L and their rotation are accomplished in the order named by the movement of cams 105, 106 and 107 into the path of the corresponding mechanisms.

The mechanisms, shown in detail in Figs. 10 and 11, as mounted on the shafts 69 and 62, respectively, each comprises a hollow member 81 in which a block 84: is fixedly mounted. A member 80, having a pair of teeth 82 on one end, is slidably mounted in each block 84 and is so movable as to bring the teeth 82 into and out of engagement with the adjacent gear 72 or 68. The member forming part of the mechanism mounted on the shaft 62, is connected by a pair of links 86 with a bell crank and the member 80 forming part of the mechanism mounted on the shaft 69 is connected with a bell crank 91 by a pair of links- 86. The bell cranks 90 and 91 are each pivotally mounted on a pin 89 and are connected with the outer ends of the links 86 by pins 88. The other ends of the links 86are connected with the member 80 by a pin 87. Both of the mechanisms shown in Figs. 10 and 11 are mounted to oscillate about the shafts 69 and 62 respectively, each being connected with its shaft by a pair of downwardly projecting plates 83. Each of the mechanisms normally occupy a perpendicular position relative to the disk 19, as shown in Fig. 10 with their respective sliding members 80 and their well cranks 90 and 91 in positions corresponding to the dotted lines of Fig. 10. A plate spring 99 normally holds the bell cranks 90 and 91 in the position indicated in dotted lines for the bell crank 91. The mechanisms are each held substantially perpendicular to the disk 19, as shown in Fig. 10, by a tensile spring 96 connected at one end to the mechanism by an eye-bolt 97 and at the other end to the disk 19 by an eye-bolt 98, as best shown in Fig. 6. A lug 100 on the rear face of the disk 19 provides a mounting for a set screw 101, utilized for adjusting the device as hereinafter more particularly described. The mechanisms are rotated relative to the disk 19 about their re speetive shafts 69 and 62, from the position shown in Fig. 10 to the position shown in Fig. 11, by contact of the bell cranks 91 and 90 with cam members 106 and 105, respectively. The cam members 106 and are normally positioned in a pocket 124C in the disk 125 and are movable out of the pocket 124: into the respective paths of the bell cranks 91 and 90 by levers (not shown). In use with airplanes, the levers are mounted within easy reach of the pilot who is enabled thereby to move the cams 105 and 106 into and out of the pocket 12% by actuating the levers, such levers each being connected by means of a rope or cable 108 with one of a pair of arms 109pivotally mounted on a rod 110. The ends (not shown) of the rods 110 are attached to the casing 18, and by actuating a levercto exert a pull on a cable 108, the corresponding arm 109 is rotated about the corresponding rod 110 thereby causing longitudinal movement of a rod with which the arm is connected.

The cams 105 and 106 are each mounted on the forward end of one of the rods 115. The rods 115 are supported by a guide plate 112 which terminates at each end (not shown) in the casing 18 which forms a support therefor.

The rods 115 are connected at their rear ends with the arms 109 by pins 113. The pins 113 are slidable in a slot 111 in the arm 109 so that oscillation of the arms-109 imparts only longitudinal movement to the rods.

In the position shown in Fig. 7, wherein the cam 106 has been moved into the path of the mechanism shown in Fig. 10, the disk 19 in revolving in counter-clockwise direction as observed in Fig. 10 brings the upper end of the bell crank 91 into contact with the cam 106. The bell crank 91 is in the dotted line position shown in Fig. 10 when it initially contacts with the cam 106 and is permitted to be moved to the full line position by such initial contact by reason of the yielding of the spring 99. In the full line position of the bell crank 91, the member 80 is moved inwardly to its full line position with the teeth 82 meshing with the gear 72. The spring 96 yields after operative engagement of the teeth 82 with the gear 72 to permit the mechanism to move to a position corresponding to that of the mechanism shown in Fig. 11, thereby actuating the gear 72 and the shaft 69 to rotate the blades 15R and 15L as hereinbefore described. The spring 96 is purposely made much stronger than the spring 99 so that the latter yields sufficiently to permit engagement of the teeth 82 with gear 72 before rotation of the mechanism about the shaft 69 starts. The continued rotation of the disk 19 carries with it the shaft 69 on which the mechanism is mounted, and such mechanism will be caused to take the position of Fig. 11 relative to the disk 19 by the contact of the bell crank 91 with the cam 106, following which the crankshaft 91 will be disengaged from the cam 106. The spring 96 will then operate to pull the mechanism back to a position substantially perpendicular to the disk 19 as shown in Fig. 10, and at the same time, the spring 99 moves the crank shaft 91 from its full line position back to its dotted line position, thereby releasing the member 80 from engagement with the gear 72. The shaft 69 is rotated a substantial amount each time that the disk 19 revolves, with the cam 106 in the path of the mechanism shown in Fig. 10, and a corresponding movement of the propeller blades 15R and 15L results. The mechanism shown in Fi 11 is actuated the same way as that described for the mechanism shown in Fig.

'10, by moving the cam 105 into the path of dinal axes at all times except when their angle of inclination is to be changed, it is necessary that means he provided for releasing the teeth 51 from operative engagement therewith, immediately before and during the interim that the cams either 105 or 106 are in engagement with their respective actuating mechanism-s. For this purpose the cam 107 is so positioned intermediate the cams 105 and 106, as best shown in Figs. 2 and 7 that either of the cams 105 and 106, when moved into the paths of their respective mechanisms, will carry with it the cam 107. The cams 105 and 106 are operable from the pilots cab by separate levers and only one of the cams 105 or 106 is to be moved into the path of its mechanism at a time. A thrust plate 116 is mounted on each of the cams 105 and 106 in such a way that when either of the cams is moved out of the pocket 12 1 into the path of its actuating mechanism, the plate 116 will carry with it the cam 107. Cam 107 is mounted on a rod 118 positioned parallel to and midway between the rods 115. The rod 118 is slidably mounted in the plate 112 and the plate 114, the latter serving as a stop limiting the amount of rearward movement of the cams. A compression spring 121 surrounds the rod 118 with one end bearing against the plate 114 and the other against a ring member 119, held in position by a pin 120. The spring 121 tends-constantly to hold the cams 105, 106 and 107m the pocket 12 4, and when the cams are moved into the path of their respective actuated devices, such movement is accomplished against the resistance of the spring 121. The cam 105 or the cam 106 having been moved into the path of its respective actuating device by a pull on the lever from the pilots cabin (not shown), such cam is locked in its extended position by means of a trip rod 125 extending through an aperture 129 in the disk 25 with its extreme end portion 128 projecting slightly beyond the front face of the disk. The rear end of the rod 125 is turned laterally to form a stem 127 which engages with a lug 117 formed on the adjacent rod 115. A compression spring 133 positioned in a socket 134 tends to keep the stem 127 in contact with the upper edge of the rod 115. When the rod 115 is moved forward to bring the corresponding cam 105 or 106 into operative position the stem 127 slides over and drops in back of the lug 117 when the cam has reached the desired position. The compression spring 121 mounted on the rod118 holds the stem 127 against the rear end of the lug 117 and cooperates with the spring 133 to keep the trip rod 125, in the position shown in Fig. 7, on the particular rod 115 which is connected with the cam 106. A trip plate 130, mounted on the rear face of the disk 19, provides means for releasing the trip rods 125 from holding engagement with the lugs 117 on the estates rods 115. The plate 130 has fingers 131 and 132 each respectively positioned to contact, as best shown in Fig. 8, with one or the projecting ends 128 of the trip rods 125 pushing the same down against the resistance of the spring 133 thereby elevating the other end of the rods 125 and the stems 127, and disengaging the latter from the lugs 117 The resilience of the spring 121 moves the cam 107 and the plate 116 back into the pocket 12?: carrying along cam 106. In the same way, it the earn 105 has been moved out or the pocket 12 1 by its actuating lever, the release or its trip rod 125 will permit the cam 107 to move back carrying with it the cam 105. The position of the plate 130 is such that the dish 19 makes substantially three-fourths of a revolution after the fingers 131 and 132 have contacted with the ends 128 of the rods 125, thereby giving time for the cam 105 or the cam 106 to be moved back into the path of the corresponding actuating device if it is desired to repeat the steps and continue the change of inclination of the blades 15R and 15L.

As observed in Fig. 2, the cam 107 which is positioned between the cams 105 and 106 is substantially longer than either of the other cams, and as a result when either of the cams 105 or 106, is in its extended position, the cam 107, which has been extended, contacts with a cam roller 76 mounted on a member 75 which connects the rods 57. The cam 107, being longer than either of the cams 105 or 100, contacts with the roller 76 in advance of contact or" either of the adjacent cams with their respective bell cranks 90 and 91. The cam 107 immediately upon contacting with the roller 7 6 forces the member 75 towards the disk 19. The movement of the member 75 causes longitudinal movement of the rods 57 on which the blocks 56 are mounted. The longitudinal movement of the'rods 57 rotates the cams 5lto positions where the sleeves 41 are spread sulhciently to remove the teeth 51 from engagement with the blades 15R and 15L, as described above. The release of the blades 15R and 15L is accomplished immediately before the earn 105/ or 106 acts on the gear and worm devices already described to cause rotation of the blades.

The projection of the cam 107 rearwardly or its companion cams 105 and 106 operates to hold the teeth 51 disengaged from the blades 15R and 15L for an instant after rotation ofthe blades has been completed, and then the teeth return to their position in the apertures 50 where they serve to lock the blades against further rotation.

Since it is desirable that the teeth 51 be in exact registry with the apertures 50 whenthe partial rotation of the blades is complete, means is provided to adjust the position of the blades relative to the encompassing sleeves 34 and t1. For this purpose, screw bolts 101 are mounted in lugs 100 on the rear face of the disk 19, as shown in Fig. 10. The ends of the bolts 101 provide stops against which the cam actuated devices rest by reason of the pull of the springs 96. llt is obvious that a slight variation 0t the position of the actuated device relative to the disk 19, will change the starting and stopping points of the rotating movement or the blades, and that a relatively slight movement of the bolts 101 will accomplish any desired adjustment at the teeth 51 relative to the apertures 50 in the blades 15R and 15L.

Thus, it will be seen that the invention provides means for automatically locking and unlocking propeller blades for the purpose of adjusting the angle ofinclination, whereby the rotation of the propeller is utilized to change the angle of inclination of the blades, as desired, and to unlock and lock the blades, and that in the case of air-craft propellers, this unlocking, adjustment and relocking, can be accomplishedby the pilot, regardless of the elevation or the speed at which he is traveling. In the absence of a second set of cams and actuating means the thickness of the disk 20 opposite to the cams can be increased to counter-balance the wei ht of the cam mechanism.

aving thus described my invention, it is obvious that various immaterial modifications may be made in the same without departing from the spirit thereof, andl do not wish to be understood as limiting mysel'l to the exact form, construction, arrangement and combination of parts herein shown and described, or uses mentioned.

l/Vhat 1 claim as new and desire to secure by Letters Patent is:

1. In a propeller, a rotatable shaft, a member providing bearing support for the shaft, radially extending blades rotatable with the shaft, bearings for said blades permitting their axial rotation, mechanism rotatable with the shaft and operable to rotate the blades a predetermined amount about their axes, means locking said blades against rotation, cam means mounted on said support and movable into the paths of said locking means and actuating mechanism, the resulting contact of said locking means with said cam mechanism operating to unlock said blades, and the resulting contact of said actuating mechanism with said cam means operating to cause said mechanism to rotate said blades, and trip means operable to move said lockin means into locking engagement with said lades upon completion of said predetermined amount of rotation of the blades.

2. In a propeller, a rotatable shaft, a member providing bearing support for'the shaft, radially extending blades rotatable with the shaft, bearings for said blad s permitting aeiasea their axial rotation, mechanism rotatable with the shaft and operable to rotate the blades about their axes, means locking said blades against rotation, cam means mounted on said support and movable into the path of said locking means, cam means mounted on said member and movable into the path of said actuating mechanism, the resulting contact of said locking means With said first mentioned cam means operating to unlock said blades, and the resulting contact of said actuating mechanism with said second mentioned cam means causing said mechanism to rotate said blades. I

3; In a propeller, a rotatable shaft, a member providing bearing support for the shaft, radially extending blades rotatable with the shaft, bearings for said blades permitting their axial rotation, mechanism rotatable with the shaft and operable to synchronously rotate the blades about their axes, means locking said blades against rotation, cam means mounted'on said support and movable into the path of said locking means, cam means mounted on said member and movable into the path of said actuating mechanism, the resulting contact of said locking means with said first mentioned cam means operating to unlock said blades, and the resulting contact of said actuating mechanism with said second mentioned cam means'causing said mechanism to rotate said blades synchronously.

4. In a propeller, a rotatable shaft, a member providing bearing support for the shaft, radially extending blades rotatable With the shaft, bearings for said blades permitting their axial rotation, mechanism rotatable with the shaft and operable to rotate the blades about their axes, means locking said blades against rotation, cam means mounted on said support and movable into the path of said locking means, cam means mounted on said member and movable into the path of said locking means, cam means mounted on said member and movable into the path of said actuating mechanism, the resulting contact of said locking means with first mentioned cam means operating to unlock said blades, and the resulting contact of said actuating mechanism with said second mentioned cam means causing said mechanism to rotate said blades a predetermined amount, and trip means operable to move said looking means into locking engagement with said blades upon completion of said predetermined rotation of the blades about their axes, in one direction.

5. In a propeller, a rotatable shaft, a member providing bearing support for the shaft, a pair of radially extending'blades rotatable with the shaft, bearings for said blades permitting their axial rotation, mechanism rotatable with the shaft and operable to rotate the blades about their axes in one direction,

a secondmechanism rotatable with the shaft and operable to rotate said blades in opposite direction, means locking said blades against rotation, cam means mounted on said member and movable into the paths of said looking means and mechanism, the resulting contact of said locking means with said cam means operating to unlock said blades, the result ng contact of said first mentioned actuatag mechanism with said cam means mitting their axial rotation, mechanism rotatable with the shaft and operable to synchronously rotate the blades about their axes in one direction, a second mechanism rotatable with the shaft and operable to synchronously rotate said blades in the opposite direction, means locking said blades against rotation, cam means mounted on said support and movable into the paths of said locking means and mechanisms, the resulting contact of said locking means with said cam means operating to unlock said blades, the resulting contact of said first mentioned actuating mechanism with said cam means causing rotation of said blades in one direction, and

the resulting contact of said second mentioned actuating mechanism with said cam means causing rotation of said blades in the opposite direction. 7. in a propeller, a rotatable shaft, a member providing bearing support for the shaft,

a pair of radially extending blades rotatable with the shaft, bearings for said blades permitting their axial rotation, mechanism rotatable with the shaft and operable to rotate the blades about their axes a predetermined amount in one direction,a second mechanism rotatable with the shaft and operable to rotate said blades a predetermined amount in the opposite direction, means locking said blades against rotation, cam means mounted on said support and movable into the path of said locking means and mechanisms, the resulting contact of said locking means with said cam means operating to unlock said blades, the resulting contact of said first mentioned actuating mechanism with said cam means causing rotation of said blades in one direction, and contact of said second mentioned actuating mechanism with said cam means causing rotation of said blades in the opposite direction.

8. In a propeller, a rotatable shaft, a member providing bearing support for the shaft, a pair of radially extending blades rotatable with the shaft, bearings for said blades permitting their axial rotation, mechanism rotatable with the shaft and operable to rotate the blades about their axes-a predetermined amount in one direction, a second mechanism rotatable with the shaft and operable to rotate said blades a predetermined amount, in the opposite" direction, means locking said blades against rotation, cam means mounted on said support and movable into the path of said locking means and mechanism, the re-' sulting contact of said locking means with said cam means operating to unlock said blades, the resulting contact of said first mentioned actuating mechanism with 'said cam means causing rotation of said blades in one direction, the resulting contact of said second mentioned actuating mechanism with said cam means causing rotation of said blades in the opposite direction, and trip mechanism operable -to move said locking means into locking enga ement with said blades upon completion 0 said predetermined rotation of the blades in either direction about their axes.

9. In a propeller, a rotatable shaft, a member providing bearing support for the shaft, a plurality of radially extending blades rotatable with the shaft, mechanism rotatable with the shaft and operable to rotate the blades about their axes in either direction, a pair of actuating members one operable to actuate said mechanism to rotate said blades in one direction and the other operable-to oppositely actuate said mechanism to rotate said lades in the opposite direction, means looking said blades against rotation, a pair of cam members mounted on said support each normally positioned out of the path of said actuating members and separably movable into the path of an ad acent actuating member, a third cam mem er so connected with each of said first mentioned cam members as to be moved into the path of said locking means when either of said pair of cam members are moved into the path of its adjacent actuating member, said third cam member being so positioned as to contact with said locking means in advance of the contact of either of said pair of cam members with its corres onding actuating member.

10. n a propeller, a rotatable shaft, a member providing bearing support for the shaft, a plurality of radially extending blades rotatable with the shaft, bearings for said blades permitting their axial rotation, mech' anism rotatable with the shaft and operable to rotate the blades about their axes in either direction, a pair of actuating members one operable to actuate said mechanism to rotate said blades in one direction and the other operable to, oppositely actuate said mechanism to rotate said blades in the opposite direction, means locking said blades against rotation, a pair of cam members mounted on said support each normally positioned out of the path of said actuating members and separably movable into the path of an ad- 'jacent actuating member, a third cam member so connected with each of said first mentioned cam members as to be moved into the path of said locking meanswhen'either of said pair of cam members are moved into the path of its adjacent actuating member, said'third cam member being so positioned as to contact with said locking means in advance of the contact of either of said first mentioned cam members with the corresponding actuating member, and a pair of control levers separably operable to actuate said pair of cam members.

In witness whereof, I hereunto subscribe my name this 10th day of May, A. D. 1930.

FERDINAND A. GILL. 

